Systems configured to transmit audible signals, such as verbal communication, between a user and an end user utilize echo cancellation. Echo cancellation functions to prevent the end user of a remote cellular phone from hearing his/her own voice. For instance, without echo cancellation, the end user's verbal communication is transmitted to the cabin from a speaker, picked up by a microphone of a system, and transmitted back to the end user of the cellular phone.
Referring to FIGS. 1A and 1B, a system is illustratively shown mounted to a platform. The platform includes at least one speaker and a microphone. The system is configured to transmit sounds through the speaker and process and transmit sounds picked up by the microphone to a remote communication device. For illustrative purposes, FIG. 1A shows the platform being an automotive vehicle having four speakers, one at each corner of the cabin space, and a microphone mounted adjacent to the driver-side A-pillar. As shown, each speaker is positioned away from the microphone at different distances, as indicated by Da1, Da2, Da3, and Da4 respectively.
With reference now to FIG. 1B, the platform is also illustrated as an automotive vehicle. The platform includes six speakers, and a microphone mounted adjacent to the driver-side A-pillar. Each speaker is positioned away from the microphone at different distances than the other, as indicated by Db1, Db2, Db3, Db4, Db5, and Db6, respectively.
The system includes a transceiver configured to receive and transmit a digital signal from and to an end user. The system further includes a processor unit in electrical communication with the transceiver. The processor unit is configured to process the digital signal from the transceiver into an auditory signal in analog form. The auditory signal is transmitted to the speakers and projected into the cabin space. The microphone is configured to receive auditory signals from within the cabin space. The auditory signal is then digitized and directed to the transceiver. The transceiver transmits the digitized signal to the remote communication device. Thus, the user of the remote communication device will hear an echo of his/her own voice.
Accordingly, it is known to apply a phase shift to the outgoing auditory signal which cancels or reduces the end user's verbal communication. Thus, the end user only hears the verbal communication from the user within the cabin space of the platform. The phase shift is programmed into the system and may be installed on a platform such as a vehicle.
However, a phase shift configured to cancel the echo is dependent upon factors such as the distance the speakers are in relation to the microphone, and the attenuation of the end user's auditory signal received by the processor unit. Accordingly, a system that is effective in cancelling echo in one platform, may not be effective in cancelling echo in a different platform. For instance, a phase shift configured to cancel an echo within the platform of FIG. 1A, may not be effective in the platform of FIG. 1B. Thus, it remains desirable to have a system which automatically tunes itself to cancel echoes so as to be adaptable for use across platforms of differing speaker configurations.